Brain cancer, and in particular Glioblastoma (GB), is a deadly disease that is in critical need of new therapies. We propose to develop biodegradable polymeric gene delivery nanoparticles to treat patients with brain cancer. Based on our recent research on evaluating a library of polymeric nanoparticles for gene delivery, ten lead structures will be synthesized and utilized to non-virally and safely deliver DNA to human Glioblastoma Multiforme (GB) cancer cells. Structure-activity relationships for ten closely related biomaterial analogs and the nanoparticles that they form will be probed in vitro in normal human astrocytes and neurospheres as well human intraoperatively obtained GB cells and GB tumor neurospheres. We hypothesize that through biomaterial and nanoparticle selection, nanoparticles can be targeted to brain cancer cells and cancer stem cells over healthy cells. A nanoparticle system will be created and evaluated in vitro and in vivo to non-virally delivery a gene that induces apoptosis in human brain cancer cells, is benign to healthy human cells, and acts in a paracrine fashion. The non-viral particles enter cells and degrade safely, releasing DNA as therapeutics that causes cancer cell death. In Aim 1, nanoparticles will be synthesized and characterized and cell assays developed. In Aim 2, mechanisms of action, cell targeting specificity, and efficacy of the nanoparticles will be evaluated in vitro. In Aim 3, the top three nanoparticle formulations will be evaluated in vivo in an orthotopic human GB mouse model. The long-term aim of this work is to create a new orthogonal clinical approach to treat Glioblastoma.